Cytoimmunologic monitoring and heart transplantation.
Cytoimmunologic monitoring (CIM) combines morphological quantitation of activated lymphocytes and immunoblasts with immunophenotyping of peripheral blood in an effort to identify patients at risk for heart transplant rejection. In this study, CIM and endomyocardial biopsy (EMB) results were correlated in 55 paired blood and tissue specimens obtained from 18 heart transplant patients after operation. We found that 83% of patients with rejection and 81% of patients without rejection had increased levels of morphological activated lymphocytes. Multiple other criteria for determining levels of activation were used without improving the sensitivity or specificity. The use of CD4:CD8 ratios to discriminate between activation caused by rejection and those from viral infections and other inflammatory conditions yielded a sensitivity of 43% and specificity of 56%. The presence of activation markers such as I2, TAC, and T9 did not correlate with either CIM or EMB findings. CD4:CD8 alone was not predictive of cardiac rejection as increased, normal, and decreased CD4:CD8 ratios were seen in patients with and without rejection. Other measurements such as percentage of activated lymphocytes, total lymphocyte count, and whole blood cell count did not correlate with EMB or immunophenotypic findings. These results indicate that neither CIM, as currently conducted, nor immunophenotyping alone is sensitive or specific enough to substitute for EMB in screening for tissue rejection.